这个我做的保存值是：*

SharedPreferences prefs = getSharedPreferences("PREFERENCE",MODE_PRIVATE);
    boolean firstrun = prefs.getBoolean("firstrun",true);

    db = openOrCreateDatabase("value.db",Context.MODE_PRIVATE,null); // optional CursorFactory

    if (firstrun) {
          SharedPreferences.Editor editor = prefs.edit();

          db.execsql("CREATE TABLE startValue (ID Integer Primary Key,myValue Integer)");

          db.execsql("INSERT INTO startValue (myValue) VALUES (2)"); 

          editor.putBoolean("firstrun",false);
          editor.apply();

           }

    // Save the state
    getSharedPreferences("PREFERENCE",MODE_PRIVATE)
        .edit()
        .putBoolean("firstrun",false)
        .commit();

而为了清除另一个活动的预告是：

try{
            db = openOrCreateDatabase("value.db",null); // optional CursorFactory

            db.execsql("DROP TABLE IF EXISTS startValue");
            db.close();

            SharedPreferences preferences = getPreferences(0);
            SharedPreferences.Editor editor = preferences.edit();

            editor.remove("firstrun");
            editor.clear();
            editor.commit();

            this.finish();
        }    
        catch(sqlException ex)
        {
        //catch error here
        }

问题

但是当我看到它没有清除偏好的时候我进行测试.我做错了吗？